Using the hash in MOKx to blacklist kernel module

This patch set is base on the efi-lock-down and keys-uefi branchs in David Howells's linux-fs git tree.
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=keys-uefi

The main purpose is using the MOKx to blacklist kernel module.

As the MOK (Machine Owner Key), MOKx is a EFI boot time variable which is maintained by shim boot loader. We can enroll the hash of blacklisted kernel module (with or without signature) to MOKx by mokutil. Kernel loads the hash from MOKx to blacklist keyring when booting. Kernel will prevent to load the kernel module when its hash be found in blacklist.

This function is useful to revoke a kernel module that it has exploit. Or revoking a kernel module that it was signed by a unsecure key.

Except MOKx, this patch set fixs another two issues: The MOK/MOKx should not be loaded when secure boot is disabled. And, modified error message prints out appropriate status string for reading by human being.

v2:
Chekcikng the attributes of db and mok before loading certificates.

Lee, Chun-Yi (5):
MODSIGN: do not load mok when secure boot disabled
MODSIGN: print appropriate status message when getting UEFI
certificates list
MODSIGN: load blacklist from MOKx
MODSIGN: checking the blacklisted hash before loading a kernel module
MODSIGN: check the attributes of db and mok

 certs/load_uefi.c       | 92 +++++++++++++++++++++++++++++++++++--------------
 include/linux/efi.h     | 25 ++++++++++++++
 kernel/module_signing.c | 62 +++++++++++++++++++++++++++++++--
 3 files changed, 152 insertions(+), 27 deletions(-)

2.10.2